There is a current requirement for a simple and reliable nitric oxide (NO) sensor in the diagnosis and treatment of respiratory distress. SRD Corporation has the technical expertise to provide an NO monitor. The proposed sensor combines the high level of selectivity offered by chemiresistive technology and the high level of sensitivity offered by SAW technology while maintaining the excellent stability of both components. Our partners at the Maine Medical Center (MMC) will provide the required medical and clinical input to the project. The investigators intend to demonstrate the viability of our sensor concept in addressing this problem under Phase I by demonstrating that the sensor can detect NO below 500 parts per billion (ppb) without interference from humidity or such potential interferents as CO and CO2. The Phase II effort will focus on refining the prototype to obtain low ppb detection levels and demonstrating its applicability to the clinical setting. In Phase II, the device prototype will be packaged in an instrument similar to current CO2 capnometers and will be employed in a clinical setting to measure NO levels of expired air in patients under respiratory distress.